Fever

Fever is defined as a temporary elevation of the body temperature, usually due to an underlying illness. Medically, fever is termed as pyrexia or febrile response and is defined as having a temperature above the normal range due to the entry of a pathogen (a bacterium, virus, or other microorganisms that can cause disease) or foreign particle.

It is caused due to numerous reasons but infections are the most common cause. Fever is generally a sign that there is some disturbance in the body caused by a pathogen and that the body is trying to fight it off on its own. Fever usually doesn’t last for more than a few days (2-5 days maximum) depending upon the causative agent and your body’s immunity. There are over the counter drugs available to bring the temperature down but if the fever is mild, it is better to leave it untreated if it is within the normal range.

Fever is classified based on the symptoms or bouts in a defined time period or as per a well -defined pattern. It is classified as:

• Continuous fever
  The body temperature remains above normal throughout a 24-hour period but does not fluctuate by more than 1°C. It occurs in typhoid, UTI (urinary tract infections) and typhus.
• Remittent fever
  The body temperature remains above normal throughout a 24-hour period but does not fluctuate by more than 2°C. This type of fever is associated with typhoid and infective endocarditis.
• Hectic or Septic fever
  The temperature variation between the peak and the normal value is very wide and exceeds 5°C. This is seen in conditions such as septicemia (the presence of infection in the blood).
• Pal-Ebstein fever
  There are alternate fever and non-fever periods during the day. The temperature may take 3 days to rise, remain high for 3 days, and then remit in 3 days, followed by more fever for 9 days. This type of fever occurs in Hodgkin’s Lymphoma.
• Low-grade fever
  Fever is present for several days but does not exceed 37.8°C at any time. Usually, it does not indicate any particular disease, but it is associated commonly with tuberculosis.
• Step-ladder fever
  Temperature rises gradually to a higher level with each spike, so that a new plateau is higher than the preceding one, just like steps of a ladder. Examples include typhoid fever.
• Relapsing fever
  Febrile episodes (fever) are separated by intervals of normal temperature. The fever when occurs may last from 2-9 days and then temperature gets normal. But, it may relapse after a period of few days repeating the same cycle. Such a pattern is seen in Borrelia infections.
• Inverse fever
  The temperature rises early in the morning rather than in the evening such as in miliary tuberculosis.
• Night Sweats
  A rise in body temperature is evident in the evening hours or the person may wake up at night due to sweating. Night sweats are common in tuberculosis, leukaemias, autoimmune disorders, and AIDS.
• Intermittent fever
  The temperature rises for only some hours in a day and remains normal throughout the remaining hours. Examples include Malaria, kala-azar, septicaemia. It has the following subtypes:-
  • Quotidian: Spike in temperature occurs daily.
  • Double quotidian: The body temperature rises twice in a day, mostly during morning and evening such as in miliary tuberculosis.
  • Tertian: A rise in body temperature occurs every alternate day such as in malaria.
  • Quartan: The temperature rise occurs every third day such as in Malaria.

Fever can also be classified as acute, sub-acute, and chronic based on the duration of fever. Acute fever (2 weeks duration) is a characteristic feature of viral infections and upper respiratory tract infection. Sub-acute type of fever (usually not more than 2 weeks in duration) is seen in people with typhoid and intra-abdominal abscess. Chronic or persistent fever (>2 weeks duration) is typical of chronic bacterial infections such as tuberculosis, viral infections like HIV, cancers, and connective tissue diseases. However, any cause of acute fever can become persistent or chronic if untreated.

Stages of fever are classified as follows:

Of all the manifestations of infection in humans, fever is the most common and most constant one. Fever can be accompanied by the following symptoms:

• Feeling hot
• Sweating
• Chills and shivering
• Headache
• Delirium (mental confusion)
• Muscle pains
• Loss of appetite
• Irritability
• Skin flushing
• Palpitations
• Dizziness or fainting
• Restlessness
• General weakness

Infections or entry of a foreign particle is usually the cause of the fever. Fever is the body’s defence mechanism to fight off the effects of the foreign particle. The possible causes of fever are as follows:

• Viruses
  They cause upper respiratory tract infections like a sore throat, nasal discharge, sneezing, and sinus pain.
• Bacteria
  Diseases like Cholera, Gastroenteritis, Tonsillitis, Pneumonia, Urinary tract infections, etc. are all caused due to bacterial entry in the body.
• Chronic illnesses
  Chronic diseases like ulcerative colitis cause fever which lasts longer than 2-3 weeks.
• Tropical diseases
  Diseases like malaria and typhoid cause recurring fever.
• Drugs
  Drug fever is caused sometimes in patients who consume penicillin and cephalosporins, sulphonamides, anticonvulsants etc.
• Cancer
  Malignant (cancerous) tumours affecting any body part. may also cause fever.
• Alcohol consumption
  Consuming alcohol above normal tolerable limit leads to liver cirrhosis (liver damage and irreversible scarring of the liver) causing fever.
• Skin disorders
  Skin diseases like a rash may also lead to a rise in body temperature.
• Heat exhaustion.
• Inflammatory conditions like rheumatoid arthritis
  Rheumatoid arthritis, which is a condition where the person has inflammation of the joints may also lead to the development of a fever.
• Immunizations and vaccinations
  Vaccinations like DTaP vaccine, pneumococcal vaccine, tuberculosis vaccine, etc. also cause fever in children.
• Unknown cause
  Sometimes, a specific cause of fever isn’t known. This is termed as PUO (Pyrexia of Unknown Origin)

Risk Factors

There are certain factors which make some people more prone to infections, thereby increasing their risk of developing a fever. These include:

• Age
  Children are at a greater risk of contracting any disease and developing a fever. It can be due to low immunity or coming in contact with affected children at school or play areas. Adolescents can also acquire fever when they come in contact with co-workers, while travelling, etc.
• Contact
  The pathogens spread by any means like air, water or food or even a vector. Therefore, coming in contact with an affected individual directly or indirectly can increase your risk of getting a fever.
• Immunity
  People with a weak immune system caused by previous infections or an active pathogen (AIDS) or medications such as corticosteroids can develop fever more frequently.
• Poor hygiene
  Improper hygiene habits can cause easy entry of pathogens and cause fever.
• Cancer
  Malignant (cancerous) conditions like lymphoma or leukaemia can cause fever at the onset of the disease or can also be recurrent.

In most cases where fever is due to infections, it is possible to prevent the risk of contamination by following certain precautions Some tips to prevent the occurrence of fever are:

Practice good hygiene habits

• Wash your hands often and teach small children to do it as well, especially before meals, after using the toilet, after spending time with someone who is sick, and after using public transport can help in preventing the spread of infections.
• Carry a hand sanitizer when you don’t have access to soap and water.
• Try not to touch your sense organs like eyes, nose or mouth when you feel your hands are dirty and need a thorough washing.
• Cover your mouth when you sneeze if you have a fever or try to move away if someone is about to sneeze to prevent germs from entering your body.
• Avoid sharing utensils and water bottles with strangers or people affected by any disease.
• Avoid travelling to places where you may contract allergies and fever such as hay fever.
• Control and eradicate breeding sites of mosquitoes in your surroundings to protect yourself from malaria and dengue fever.
• Get vaccinated with flu vaccines.

Fever occurs when there is some infection or foreign particle in your body which is not allowing your body to function normally. It is not an illness but is indicative of an underlying infection or other diseases. The underlying cause of fever must be found out so as to begin a specific treatment. If the cause of fever is not clear, then the doctor may take a detailed medical history of the patient and check for different signs which may give a clue to the underlying cause of the fever. Some common tests which a doctor may prescribe are as follows:

• Blood tests (including differential White blood cell count)
• Urine examination and culture
• Throat swabs or mucus sample examination and culture
• Stool examination and culture
• X – Rays.

At home, recording the temperature using a thermometer can help in understanding the pattern of fever. There are 4 common sites where thermometer can be placed to measure the body temperature. They are:

• Axilla (under the armpit)
  The tip of the thermometer is placed under the armpit. Gently press the arm down so that the position of the tip of the thermometer is unchanged. Keep it in position for 1 minute. Generally, the readings from the armpit are 1°C lower than the actual temperature. So, adjust the final readings accordingly and record it for the doctor, if he/she asks.
• Eardrum
  Tympanic thermometers must be placed in a correct way in case of a child. Earwax can give inaccurate readings though.
• Oral
  People aged 4 years or older should have their temperature taken by mouth. The tip of the thermometer is kept under the tongue with their mouth closed properly as any mouth opening can cause an inaccurate reading. Keep the thermometer for about a minute.
• Rectal
  This method is used in children below 3 years of age. It gives an accurate reading. The rectal temperature will be approximately 1°C higher than the body temperature. So, adjust the reading accordingly.

If the fever is mild and non-recurrent, then ideally no treatment is required as it will subside on its own. Fever is a body’s defence mechanism to fight against microorganisms. Microorganisms cannot survive due to temperature fluctuations in the body. There are some simple steps which can be taken to tackle fever or symptoms arising from it. They are:

• Drink enough fluids which help cool down your body and prevent dehydration.
• Have easy to digest foods until your fever subsides.
• Take adequate rest.
• Take a bath with lukewarm water.
• Do cold compresses. Apply damp cloth on the forehead to cool down body temperature.
• Keep a fan on to circulate fresh air.

OTC (over the counter) drugs like paracetamol can be effective in reducing mild fever. But if diagnosis via a blood test reveals an infection then appropriate treatment plan must be followed based on the doctor’s advice. The doctor may prescribe some antibiotics as well as antipyretics to help treat the disease.

Infants may need hospitalisation if fever persists even for a couple of days.

Lifestyle management

Fever is a common symptom that can be caused by any small change in the body’s working pattern due to a foreign substance. Hence, there are no substantial changes that can be made to tackle it. Normally, fever can occur due to stress or overworking of the body or lack of rest. If so, take appropriate measures to eliminate the cause. Take adequate rest and meditate. If a person is prone to allergies like dust or extreme sunlight/heat, which can precipitate changes in the body like cough or heat stroke, try to avoid them. Avoid travelling by public transport as there is an increased risk of catching minor infections.

Managing fever is simple as adequate rest alone may sometimes prove sufficient. Increase intake of fluids to maintain the hydration of the body and to maintain electrolytes level in the blood. Dress lightly, i.e. wear comfortable clothes and keep the room airy. Maintain personal hygiene and in the case of children, be accurate and up to date with the vaccine schedule.

Prognosis

The outcome of fever is good if the cause is known and can be treated with an effective treatment plan prescribed by the doctor. But, sometimes fever which is without a known cause (PUO or pyrexia of unknown origin) can prove fatal and has a poor prognosis.

Complications

Complications of fever are few and rare. It all depends on the cause and type of fever. If the fever is not treated at the right time, then dehydration is the most common complication. Still, increased fever can cause abnormal brain activity like epilepsy with seizures, coma or even death. Systemic complications can be caused if the cause of fever is related to any particular body system which can affect the body’s working. But, mortality due to fever alone is rare.